Rock Wool and Printed Circuit Boards (PCBs) as Partial Fine Aggregate Replacements in Cement Mortar

Abstract

The utilization of industrial wastes such as, fly ash, silica fumes, and slag in construction materials, has been receiving increased attention due to its environmental friendliness and reduction of natural resources consumptions. This study investigates and compares the utilization of spent rock wool from industrial insulation and printed circuit boards (PCBs) (the non-metallic part) as a partial replacement for conventional fine aggregates in cement mortar. Each of the waste materials was used as a partial fine aggregate ranging from 0% to 20%, by weight. The cement mortar samples were cured at 7 days, 14 days and 28 days. To investigate the properties of the cement mortars with different amounts of industrial wastes, the density, compressive strength, transverse strength and thermal conductivity of each mortar variation were measured. The results indicate that the compressive and transverse strengths of the cement mortars decreased as more industrial wastes was present in the mixtures. However, the fine aggregate substitutes improved thermal resistance, as indicated by the decreasing thermal conductivity values of the cement mortars. Thus, the use of these two industrial wastes in cement mortar could be a viable option for non-structural and non-load bearing construction applications because these substitutes have the ability to produce mortar with suitable mechanical and insulating properties.